Mobility is the operative word for 2011, and Wi-Fi is in the thick of the action. Worldwide there are now more than 700 million people using 1 billion Wi-Fi-enabled devices, says Edgar Figueroa, CEO of the Wi-Fi Alliance, and that user base is set to double by 2012. With 802.11n, wireless LANs can deliver throughput commensurate with copper networks, and new enhancements increase reliability.

So are businesses taking some of their 2011 budget increases and building robust back-end wireless networks to effectively support all of this gear? Our InformationWeek Analytics 2011 Wireless LAN Survey of 339 business technology professionals shows that 24% are either still evaluating or passing on 802.11 altogether, while 39% are using WLAN technology on a large scale and growing it, up from 35% last year. The remaining 37% are deploying WLANs for very specific uses only.

Our advice: Don't be caught napping when employees realize you're not helping them get maximum value from those Wi-Fi-enabled devices in their pockets. Yes, they can get access via carrier cellular networks. But as we'll discuss in more depth, despite evolving carrier upgrades from circuit-switched technologies to data-switched methods like HSPA+ and LTE, bandwidth demand will continue to outstrip supply. Carriers themselves are exploring ways to improve the user experience by off-loading some data traffic to higher-bandwidth Wi-Fi networks.

Our take is that four factors will soon make tethered user networking as we know it passé for all but the most security-conscious enterprises.

>> Demand: In our March InformationWeek Analytics 2010 Mobile Device Management and Security Survey, we asked whether portable, mobile, or fixed-location devices would grow as a percentage of all end user gear over the coming two years. Just 8% said they expect to see more desktops. The top answer (87% of respondents) was that mobile devices, including smartphones, will become more prevalent; 68% cited portable devices (laptops, netbooks, tablets). The reasons for this shift are many, but business leaders continue to see mobility and collaboration as good for the bottom line.

Though hard-dollar benefits are subjective, intuitively they're difficult to deny. Like it or not, employees will relentlessly push IT to support more, and more varied, wireless gadgets in the workplace. The increased demand will stretch your 11a/b/g network to the limit.

>> Obsolescence: It's costly to operate parallel access layers, so as all those switches reach end of life, it's fiscally irresponsible to not run the numbers and see how Wi-Fi's ROI stacks up against copper upgrades.

5 802.11n ROI Factors

Focus on these when making your case

1. Spectrum choice: 802.11n operates in both the 2.4-GHz and 5 GHz ranges.

2. Channel bonding: The ability to combine two neighboring transmission channels can more than double your data rate.

3. Transmission efficiency: With 802.11a/b/g, recipients usually acknowledge every data frame. In contrast, 802.11n's aggregation techniques place several frames of data into one transmission.

5. Legacy tolerance: 802.11n can play well with older gear. There's a cost in performance, but you won't need to upgrade all clients at once.

>> Performance: Even if your 11a/b/g network consists of quality gear and runs well, it simply doesn't have the capacity and reliability of 11n run in the 5-GHz spectrum. A single 11n access point can outpace legacy gear by five to 15 times, a major increase. When your users complain that the Wi-Fi network in your office is slower than what they have at home, the answer is 11n.

But before Wi-Fi can overtake copper, our survey shows that vendors will need to address some major concerns. Top among our survey respondents' worries: speed and performance (55%), reliability (50%), data security (49%), and consistency of experience (41%). This data is strikingly similar to last year's survey numbers. The data also explains why vendors are making major pushes to introduce WLAN management tools.

"Whereas WLAN security was the focus in the early part of the decade, discussions now focus much more on ways to increase reliability and performance by identifying RF interference," says Chris Kozup, Cisco's director of marketing, mobility solutions. That explains the development effort Cisco is devoting to its CleanAir products, which are aimed at monitoring the RF environment for transmissions that disrupt radio frequencies so that offending devices may be removed.

When making the case for upgrading or expanding the WLAN, CIOs must show that Wi-Fi will contribute to the bottom line by both untethering employees (hard to quantify) and by reducing hard-dollar capital and operational expenses over a typical five-year timeline. As we discuss in more depth in our full report, however, beware vendor sweet talk, especially when it comes to ROI. Some costs will always be subjective, but be stringent about measuring that which can be measured.

Converged Communications

The worldwide cellular voice and mobile broadband subscriber base is growing quickly, lured by an array of new devices. That smartphone-driven appetite for data is, unfortunately, crushing carrier cellular networks. One saving grace: Devices these days often contain both 3G and Wi-Fi radios. Cellular carriers are exploring ways to off-load some data traffic to higher-bandwidth Wi-Fi networks, both to relieve the pressure on their 3G/4G networks and to improve the user experience.

Steven Glapa, senior director of field marketing at Ruckus Wireless, says his company is participating in efforts to define a new "Hotspot 2.0" standard that will incorporate for combination HSPA/LTE/Wi-Fi networks the kinds of roaming agreements and back-end internetworking systems that now support cellular roaming (originally for 2G voice services). This will happen, but it will take years.

Meantime, operators are implementing Wi-Fi as a 3G data off-load complement. The standards to make subscribers' experiences on their home networks as seamless and effortless on Wi-Fi as they are on 3G exist today and are already on many mainstream smartphones. Achieving this involves leveraging the IEEE 802.1X standard and its EAP-SIM variant for secure, automatic (zero-touch) authentication between smartphones and access points, and the 3GPP 23.234, or I-WLAN, standard to govern how authentication and policy implementation are handled back at the mobile operator's core network. Glapa says that most operators' 3G core network infrastructures are capable of supporting enough of the I-WLAN reference architecture to accomplish seamless data off-load, and that Ruckus is seeing a fundamental shift in mobile operators' attitudes about Wi-Fi. Rather than considering it a Band-Aid for isolated capacity problems, they're thinking of 802.11 as a strategic asset that complements their licensed band technologies over the long term. We discuss these issues in more depth in our full report.

Architectural Matters

When 802.11 first made inroads, WLANs consisted of fully distributed, autonomous access points. This approach eventually evolved into a centralized model, with one "brain" to control most operations. Now another upheaval is at hand. Vendors have recognized that in light of 11n's ability to jam much more data between RF and copper, there are scaling limitations around using a controller for a "what's next" decision.

Enter a new distributed model, where access points have relationships with a management controller but don't rely on it for forwarding and policy decisions, such as quality of service and firewalling. Aerohive has been a leader here, and some big vendors, including Aruba and Motorola, have been converting their platforms to follow suit. Cisco, however, appears to not be evolving its architecture in this way, likely because doing so could cannibalize its current business. We think that the new distributed model is the way to go, but make sure that any candidate vendor is indeed processing all data-plane (forwarding operations) and all control-plane (policy operations) at the access point and not the controller. Some vendors are able to do this only partially or they have limits on the number of APs that can operate fully distributed.

The WLAN landscape is in flux, with many respondents to our survey unsure of their situations. Our advice: Talk to your vendors. You may be pleasantly surprised by WLAN advances. Don't think you must rip and replace; 11n works with legacy gear, and in our best-practices report on managing mixed WLANs, we discuss how to maximize performance when you can't update all at once.

When researching WLAN purchases, have vendors articulate how the associated capital and operating expenditure costs will compare with copper networks. Be aware of 802.11n prerequisites. Since 11n networks can be much faster than legacy 11a/b/g, data bottlenecks are more apt to occur on the wired infrastructure side. Controllers can be bottlenecks, too, so consider fully distributed architectures that are still centrally managed. Realize that 11n access points, depending on their design, may need more power than 11a/g units. If a vendor says you don't need to upgrade your older Power over Ethernet system to power its 11n gear, get a demo.

Ensure that those responsible for provisioning end user devices are in the loop. To take advantage of 11n, client computers must be 11n-capable. All new purchases should feature dual-band Wi-Fi cards so that they can operate in either the 2.4-GHz or 5-GHz spectrum. Create a client NIC hardware specification, and plan new purchases accordingly. Don't skimp on staff training and diagnostic tools, such as spectrum analyzers and wireless frame analysis software. Finally, consider regulatory compliance and fitting the WLAN into your security program. Use enterprise-grade authentication and encryption. Specifically, employ WPA2 wherever possible, along with a strong authentication method that's compatible with your back-end user directory and compliant with your security policy and risk profile.

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